The present invention relates to a metal laminate gasket of a very thin type.
A conventional metal laminate gasket is constructed by laminating several plates, and is provided with a complicated sealing portion around a hole to be sealed. Consequently, it is difficult to manufacture a metal laminate gasket with light weight. Also, productivity of a metal laminate gasket is poor. As a result, a metal laminate gasket is more expensive than other gaskets.
In a small engine, a gasket must be light in weight and manufactured at a low cost. However, a conventional metal laminate gasket is heavy and expensive. Therefore, a conventional metal laminate gasket is not usually used for a small size engine.
In U.S. Pat. No. 4,834,399, a gasket formed of two plates was proposed, wherein an area around a hole is sealed by one or two sealing means formed on the plates. The gasket can securely seal around the hole as intended. However, the gasket is not suitable for sealing around a hole where a large force is applied, e.g. an engine with high compression ratio.
In the above patent, two sealing means may be formed around the hole at a distance away from each other. In this case, even if bolts are tightened equally, the two sealing means situated away from each other may not be equally tightened. Especially, in case high tightening force can not be applied to the engine parts, the sealing means may not be equally compressed. As a result, creep relaxation may occur at the sealing means.
Accordingly, one object of the present invention is to provide a metal laminate gasket for securely sealing around a hole, which is light in weight and simple in structure.
Another object of the invention is to provide a metal laminate gasket as stated above, wherein sealing means can be compressed equally by its own operation of the gasket.
A further object of the invention is to provide a metal laminate gasket as stated above, which can securely seal around a hole without concentrating sealing pressure at one portion.
A still further object of the invention is to provide a metal laminate gasket as stated above, which can be easily and economically manufactured.
Further objects and advantages of the invention will be apparent from the following description of the invention.